[Docs restructuring]Before you install Fuel

Added a section that describes what steps the user must complete
before installing Fuel.
Added the workflow diagrams.

Change-Id: Ia5f655d54c7235e4ac5b36c36b704e488043cc5f
Partial-bug: #1504699

pages/draft/fuel-install-guide/install_before_you_install_fuel.rst

@@ -0,0 +1,34 @@
+.. _install_before_you_install_fuel:
+
+Before you install Fuel
+~~~~~~~~~~~~~~~~~~~~~~~
+
+Before you install Fuel, verify that you have completed the following tasks:
+
+#. Read and complete the tasks described in the following sections:
+
+   * : ref: `intro_install_overview`
+   * : ref: `sysreq_intro`
+
+#. If you use bare-metal hardware, set up and connect all hardware.
+
+#. If you use virtual hardware, configure all required virtual machines,
+   network, and storage parameters.
+
+#. Select a workflow:
+
+* If you install Fuel on a server with an Internet connection, follow this
+  workflow:
+
+.. image:: /_images/fig/d_install_w_internet.png
+   :width: 70%
+   :align: center
+
+* If you install Fuel on a server without an Internet connection, you must
+  configure a local repository and modify the default Fuel repositories, so
+  that Fuel installs the operating system packages from the local
+  repositories. Therefore, follow this workflow:
+
+.. image:: /_images/fig/d_install_wo_internet.png
+   :width: 70%
+   :align: center